Linked Life Data

15044496

Source:http://linkedlifedata.com/resource/pubmed/id/15044496

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
22
pubmed:dateCreated
2004-5-24
pubmed:abstractText
The second transmembrane domain (TM2) of neurotransmitter transporters has been invoked to control oligomerization and surface expression. This transmembrane domain lies between TM1 and TM3, which have both been proposed to contain residues that contribute to the substrate binding site. Rat serotonin transporter (SERT) TM2 was investigated by cysteine scanning mutagenesis. Six mutants in which cysteine replaced an endogenous TM2 residue had low transport activity, and two were inactive. Most of the reduction in transport activity was due to decreased surface expression. In contrast, M124C and G128C showed increased activity and surface expression. Random mutagenesis at positions 124 and 128 revealed that hydrophobic residues at these positions also increased activity. When modeled as an alpha-helix, positions where mutation to cysteine strongly affects expression levels clustered on the face of TM2 surrounding the leucine heptad repeat conserved within this transporter family. 2-(Aminoethyl)-methanethiosulfonate hydrobromide (MTSEA)-biotin labeled A116C and Y136C but not F117C, M135C, or Y134C, suggesting that these residues may delimit the transmembrane domain. None of the cysteine substitution mutants from 117 through 135 were sensitive to [2-(trimethylammonium)ethyl]methanethiosulfonate bromide (MTSET) or MTSEA. However, treatment with MTSEA increased 5-hydroxytryptamine transport by A116C. Activation of A116C by MTSEA was observed only in mutants containing Cys to Ile mutation at position 357, suggesting that modification of Cys-116 activated transport by compensating for a disruption in transport in response to Cys-357 replacement. The reactivity of A116C toward MTSEA was substantially increased in the presence of substrates but not inhibitors. This increase required Na+ and Cl-, and was likely to result from conformational changes during the transport process.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22926-33
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed-meshheading:15044496-Animals, pubmed-meshheading:15044496-Binding Sites, pubmed-meshheading:15044496-Carrier Proteins, pubmed-meshheading:15044496-Cell Membrane, pubmed-meshheading:15044496-Cysteine, pubmed-meshheading:15044496-Membrane Glycoproteins, pubmed-meshheading:15044496-Membrane Transport Proteins, pubmed-meshheading:15044496-Mutagenesis, pubmed-meshheading:15044496-Mutation, pubmed-meshheading:15044496-Nerve Tissue Proteins, pubmed-meshheading:15044496-Protein Binding, pubmed-meshheading:15044496-Protein Conformation, pubmed-meshheading:15044496-Protein Structure, Tertiary, pubmed-meshheading:15044496-Protein Transport, pubmed-meshheading:15044496-Rats, pubmed-meshheading:15044496-Serotonin Plasma Membrane Transport Proteins, pubmed-meshheading:15044496-Structure-Activity Relationship
pubmed:year
2004
pubmed:articleTitle
Analysis of transmembrane domain 2 of rat serotonin transporter by cysteine scanning mutagenesis.
pubmed:affiliation
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8066, USA.
pubmed:publicationType
Journal Article